Telephony



W. W.,`JA0QUES.

TELEPHONY.

(No Model) No. 535,289. Patented Mal.V 5, 1895.

"NITED STATES ATENT OFFICE,

WILLIAM W. JACQUES, OF NEWTON, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

TELEPHONY;I

sPnorFroA'rIoN forming part of Letters Patent No. 535,289, dated March 5, 1895.

Application filed May 26, 1892- Serial No. 434,402. (No model.)

To aZZ whom it may concern:

Be it known that I, WILLIAM W. J AcQUns, residing at Newton, in the county of Middlesex and State of Massachusetts, have invented certain Improvements in Telephony, of which the following is a specification.

It is well known that when a multitude of electrodes are maintained in loose contact with each other and an electric current of moderate strength is passed through them, these electrodes will remain normally at rest, and a telephone receiver connected in circuit will be normally silent. If, however, the strength of the current be increased, these electrodes will, at some definite strength of current, dependent upon the number and character of the electrodes and the normal pressure existing between them, break into rapid and continuous vibration to and from each other, and there will be heard in the receiving telephone a rustling sound made up of a multitude of simultaneous pitches.

Hitherto in the commercial use of multiple contact transmitters, of which the Hunnings transmitter may be considered the type, it

t has been customary to use a current which shall not be so strong as to set the electrodes in vibration. Whenever, either by accident or as an experiment, a stronger current has been used and the electrodes have been set in vibration, the telephonie system, consisting of the transmitter and its corresponding receiver, has prooved less efficient in the transmission of speech,because the resulting noise due to theV vibration of the transmitter electrodes, has acted upon the listening ear to make it less sensitive and therefore less fitted to receive and understand transmitted speech.

I have discovered that when a multitude of electrodes in loose contact are normally kept in a state of rapid and continuous vibration,

l they are much more sensitive to sound waves falling upon them than are the same contacts normally at rest. Though the discovery was in fact an accident, the explanation probably is that the resultant normal pressure existing between the various pairs of electrodes of a multitude of electrodes is less when all of the electrodes are in Vibration to and from each other, than when they are at rest; and it is Well known that, within limits, the-sensitive ness of any microphone contact increases as the normal pressure is decreased. My invention is founded in part on this discovery.

In practicing my invention, a multitude of u loose contact electrodes are kept in rapid and continuous vibration by passing through them a very strong electric current. I use a current from a low resistance battery (as, for example, a storage battery or standard Fuller bichromate battery) having an electro-motive force of about twenty volts. A much larger battery maintains the electrodes in too sensitive a condition for practical use.. Heretofore in transmitters of the Hunnings type, it has been customary to use eight volts with the Lyons and Keller form and six volts with the solid back transmitter. Ten volts have been found impracticable to use with either of these instruments for the reason that they set the electrodes in vibration. By using so strong a battery I am not only enabled to maintain the electrodes of the transmitter in the most desirable condition of sensitiveness to sound waves, but these sound waves cause the electrodes to vary the resistance of a current of much higher electro-motive force than has hitherto been found practicable to use.

I have further discovered that upon a long telephone line, undulatiousfof current due to the vibrations of the electrodes of the transmitter produced by the normal action of the battery will fade out and disappear at a greater or less distance from the transmitter; while undulations of current due to the action of sound waves upon the normally vibrating electrodes will persist andthe sounds be heard in the telephone at the distant end of the line.

The invention relates to long distance telephony and its principal feature is a new method of transmitting vocal or other sounds electrically, which consists in passing through a multitude of loose contacts in a circuit an electric current sufficiently strong to keep said contacts in continuous rapid vibration and superimposing upon such vibrations the vibrations due to sound waves.

The invention consists further in apparatus for practicing said new method. It is essential that the transmitting instrument shall be indestructible by heat resulting from the operation of the instru ment. I have never known,

IOS

prior to myinvention, of a transmitter whose constructionin thisrespect was such as vto admit of the successful practice ot' my present invention. It is also essential for talking in both directions over the line, that the current from the transmitting instrument shall not be allowed to act-with its full intensity. uponfthe telephone receiver at the transmittingend of the line.

The apparatus is shown in the accompany' ing drawings.

Figure l is a diagram representing the apparatus as a whole. The local circuits with the instruments therein atthe tw-o ends ofthemain line are duplicates each of thevother. Fig. 2 is a view of the transmitter in section. Fig. 3 represents detached portions of the same.

L is the mainline and Z, Z are thel twolocal circuits.

.I is: an induction coil at either end of' the main line electrically connecting it with the local circuit.

'I islthe transmitting telephone, Rgthe receiving telephone, and B'tne battery in either local circuit.

In the figures having special reference to the construction of the transmitting instru,- ment-,A is a cup-shaped metallic frame supporting the operative parts ofthe instrument; C isa metallic coversecured to the said frame A- by screws s.

D is the sound receiving diaphragm rigidly clamped between frame F and coverC. A mouthpiece m is screwed into a projection n from the cover as shown.

G is a cylindermade of slate-stone or other similarlitre proofinsulating material having a small coefficient ot' expansion. Itk has a flange fand is secured to the interior of the cu-p-shaped'f'rame'F by a brass ring r which rests upon said flange and is there held by screws tscrewing into the frame.

Eis the back electrode, being a disk of hard carbon brazed to a'brass disk K, a projection from which'lies, as shown,.within a hollow projection p from frame F,Qthe two said'y projections being insulated from each other-by a cup-shaped Washer w of vulcanized fiber.

P is the front or working electrode, being a diskV of hard carbon rigidly secured to the sound receiving diaphragm D'by a screw Vand nutas shown.

The two said electrodes E and P tit .thecyll inder G closely. For a variable resistance material between them I employ granulated carbon, g, the grains being of such size, varying from nineteen one-thousandths to twentyeight one-thousandths of an inch in diameter, that they willnot pass between the peripheries of1 the said electrodes E and P and* the inner wall of the said cylinder G. These grains make the numerous loose contacts, which, in the operation of 'the instrument lto practice the present invention, are keptin violent'vibration by the strength ,of the 'battery-currentwhile serving also as the variable resistance medium between the working electrode P and; the back4 electrode'E, to take up the vibrations due to vocal waves in the ordinary manner.

The back electrode E is made adjustable by means of a spring a tending to push the brass disk Kinto the cylinder Gry and a brass thumb screw b. A` flanged; washer-c of vulcanized fiber insulates frame F from the thumb screw b. The frame F, as has already appeared, is in metallic connection with the working electrode P, while the thumb screw b is in metallic connection with the back electrode E. Gonnection withastrong battery B may be made in any practical way. For very long distances, one thousand miles, I use a battery of twenty volts.

The instru mentlconstructed ofmaterials as abovedescribed andin the'manner described is proof against heatd'erived. fromv the battery in t'heoperation ofithe instrument;

In the operation.ofithevinstrument as above directed, itY would seem.: that the notesv or sounds duo to vibrations ofthe loose contacts ind'uced by the, voice, ndf reinforcement or additional strength in similar notesorsounds due to .vibrations setup by the strong battery and; reach the receiver at thev distant` endtof the,- line, while notes or sounds dueto the battery alone fail to reach the receiver at the distant endofthe line. The noise in the receiving instrument, however, resulting from the two sets ofA vibrationsinl the transmitting instrument atthe same end ofl the 1ine,When the latteris constructed andoperated as above described, is not only painful to the ear but interferes with' thel proper reception by the ear of sounds coming frompthe other end of the line. To obviate this difficulty.. I so, constructthe receiving telephonel that .the cur rent coming fromthe transmitting telephone at .the-samey endofj' the line; is divided and passes` around the core of' the receiving instrument'in two directions, v.while the current from the transmitting telephoney at the farther end of the line passes around the core alwaysr in one` direction. This winding is shown in thediagram at Fig. 1V where Lrepresents th'e'mainline, Zthelocal'circuit and .I the induction coil, from the, secondary of which -a wire Z leadsto the-core of the adjacent receiver R, about which, dividing, it is wound in two directions; one portion, Wound in one direction, going to the main line L and by thesaid mainline back to the. secondary of the induction coil', while the other portion, wound in the opposite direction, returns'to the secondary of theinduction coil by wire Z2; A resistance N isplaced in wire Z2 to equalize or'vary, as may be'd'esired, the proportions of the current' passing through L and Z2. It may perhaps be advantageous to maintain a slightly.imperfect balance in order that the user ofthe transmittinginstrument'lnay hear his own voice in the receiver.

Ifclaiml. The hereindescribed method ot' trans IIO mitting vocal or other sounds electrically, which consists in passing through a multitude of loose contacts in a circuit an electric current sufficiently strong to maintain said contacts in continuous rapid vibration, and superimposing upon such vibrations the vibrations due to sound waves.

2. The combination with a transmitting telephone containinga multitude of loose contacts and a battery of sufficient strength to keep said contacts in rapid vibration, of a differentially wound receiving telephone so connected and balanced that a current from the said transmitting telephone will pass around the core of the said receiving instrument in two directions substantially as described.

May, 1892.

WILLIAM vv. JACQUES.

Witnesses:

GEO. WILLIS PIERCE, H. R. MASON. 

